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Dan Pu



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    EP1.01 - Advanced NSCLC (ID 150)

    • Event: WCLC 2019
    • Type: E-Poster Viewing in the Exhibit Hall
    • Track: Advanced NSCLC
    • Presentations: 1
    • Now Available
    • Moderators:
    • Coordinates: 9/08/2019, 08:00 - 18:00, Exhibit Hall
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      EP1.01-33 - Extracellular Medium of Senescent Lung Cancer Cells Promoted Tumor Progression Through Activation of YAP and PD-L1 (Now Available) (ID 1335)

      08:00 - 18:00  |  Author(s): Dan Pu

      • Abstract
      • Slides

      Background

      Cellular senescence has been perceived as a barrier against carcinogenesis. However, the senescence-associated secretory phenotype (SASP) of senescent cells can promote tumorigenesis. Our previous researches revealed that the secretary cytokines from senescent cancer cells induced by bleomycin promoted migration and invasion of associated non-senescent cells, while the impact of hydrogen peroxide (H2O2)-induced senescent epithelial originated tumor cells on associated non-senescent tumor cells was rarely reported and the underlying mechanisms has not been discerned.

      Method

      Senescence was induced in human lung adenocarcinoma cancer cells (A549 and NCI-H1299) by Oxidative DNA damage chemical, hydrogen peroxide (H2O2), and verified by senescence-associated β-galactosidase (SA-β gal) staining and flow cytometry. A549 and NCI-H1299 cells were treated with condition medium of senescent/non-senescent A549 and NCI-H1299 (senescent vs. non-senescent group), and their protumorigenic roles were tested by cell viability assay, colony formation assay and cell invasion and migration assay. Label-free quantitative proteomics was performed to detect the expression of cytokines in culture medium of senescent/non-senescent A549 and NCI-H1299. To determine whether the YAP and programmed cell death ligand 1 (PD-L1) were involved in the tumorigenic roles, the protein and mRNA expression levels of PD-L1, YAP, CYR61, c-Myc and CTGF in A549 and NCI-H1299 were assessed by Western blot (WB) and quantitative reverse transcriptase PCR (qRT-PCR). To characterize senescent cells in lung cancer patients, we performed SA-β-Gal staining using fresh-frozen tissue sections from 20 normal lung samples and 40 lung adenocarcinoma cancer samples. To elucidate the relationship between YAP and PD-L1 in the same tumor tissue, immunohistochemistry detected the expression of both YAP and PD-L1.

      Result

      A549 and NCI-H1299 could be steadily induced senescence with an induced rate of more than 90% at a dose of 200uM and 100uM of H2O2, respectively. The proliferation and migration ability of cells was significantly higher in senescent than in non-senescent group. Senescent condition medium significantly promoted cell proliferation and migration in both PD-L1 high-expressing NCI-H1299 and PD-L1 low-expressing A549. However, the presence of senescent condition medium increased the proliferation and invasion of co-cultured cells was significantly less in PD-L1 low-expression A549 than that seen in PD-L1 high-expressing NCI-1299. The secrete proteins identified following H2O2 treatment included extracellular matrix protein, inflammatory cytokines, growth factors, chemokines etc. Further mechanistic investigations revealed that mRNA level of target genes of YAP (CYR61, c-Myc, CTGF) and PD-L1 were increased after H2O2 treatment and their expression were positively correlated. Besides, in senescent lung adenocarcinoma cancer tissue, PD-L1 positive lung adenocarcinoma cancer samples showed significantly higher nuclear YAP positive ratios compared to PD-L1 negative samples.

      Conclusion

      H2O2 successfully induced senescence on epithelial tumor cells A549 and NCI-H1299, whose secretary phenotype significantly promoted the proliferation and invasion of associated PD-L1 high-expressing non-senescent lung adenocarcinoma cancer cells compared with PD-L1 low-expressing NSCLC cells in vitro. PD-L1 and nuclear YAP are co-expressed in senescent lung adenocarcinoma cancer tissues, enlightening a therapeutic target of the combination of Hippo/YAP signaling pathway with immune checkpoint PD-L1/PD-1 inhibitors.

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